Conveyor system with variable spacing between the carrier units

ABSTRACT

A cartonizing machine wherein articles are arranged either individually or in groups in trays passing through a feeding station and to and through a loading station wherein the articles on the successive trays are pushed transversely into respective carton members conveyed with a mutual spacing. The filling of the trays is facilitated when the trays are closely juxtaposed with such being achieved by a tray conveyor system disposed so as to operate with a reduced tray pitch and a tray speed in the feeding station.

FIELD OF THE INVENTION

The present invention relates to a machine for cartionizing articlescomprising an endless feeder conveyor operable to successively move arow of carrier trays through a filling station, in which the carriertrays are manually or automatically filled with articles to be packed,and then through a loading station, in which the articles areautomatically pushed from the trays into erected carton members,whereafter the emptied trays are returned by the feeder conveyor to thefilling station. The loading station forms a portion of a cartonhandling line comprising a magazine for prepared flat carton members anda station for erecting the flat carton members into a rectangulartubular shape before the carton members are supplied to the loadingstation, while, after the loading station, further stationing areprovided for gluing and closing the carton. The transfer of the articlesfrom the carrier trays to the cartons may make place during a standstillor during synchronized co-motion of the carrier trays and the cartons.

BACKGROUND OF THE INVENTION:

It is desirable that such a cartonizer be adjustable to the effect thatthe cartonizer can handle different sizes of cartons and articles, forexample, such that during one period of time large size units can behandled, followed by a period of handling small size units. Here thecarton line sets a certain dimensioning limit, namely, with respect to adistance between the consecutive units. The carton line can be designedto handle carton members of a given maximum width, and it is thenpossible to use the carton line also for handling carton members ofsmaller widths, but what cannot be changed is the pitch of the cartonline. The units themselves may be narrower than those having a maximumwidth, but the distance between their centers or, for that matter,between their front or rear ends will have to be the same as for unitsof the maximum width. It will be very complicated and expensive to makethe carton line adaptable in this respect.

Particularly in connection with cartonizers designed for dynamictransfer of the articles into the carton members that is, duringco-motion of the trays and the cartons, it is necessary to make use ofthe exact pitch as far as the trays on the feeding conveyor areconcerned, such that, in the loading station, a tray can be aligned witha carton member almost before or immediately after the article on thepreceding tray is laterally transferred into its associated cartonmember.

Conventionally, this has given rise to serious problems. It is noproblem to provide the feeding conveyor with the article trays having arelevant width for the articles to be packed, as this will only be aquestion of replacing one set of trays with another set of broader ornarrower trays, but for trays narrower than the maximum width, therewill occur a certain spacing between the edges of the consecutive trays,and such spacing is highly inconvenient for a safe operation of thefeeding station. In the feeding station, it is imperative that thearticles can be placed neatly in the trays with a minimum of attentionand, particularly, in connection with manual filling of the trays, itmay well happen that the operator places an article in a tray not fullyor not all centered therein, whereafter it should be relatively easy tocorrect the positioning of the article by a simply push on the article.When the trays are of the maximum width, the tray edges will be closelyjuxtaposed, for example, one tray will be followed practicallyimmediately by another tray, and the operator can easily secure acorrect positioning of the articles on the trays. This becomes moredifficult when narrower trays with a mutual distance are used, and, frompractical experience, there are many examples of operators having filledarticles down into the open spaces between two consecutive traysresulting in sever operational disturbances. On this background, it is acommon practice that the empty spaces between trays, narrower than themaximum width, are held covered by plate elements located in the toplevel of the trays, such that the operator can not loose any article,but rather easily scrape a misplaced article into the relevant tray.However, these added plate elements exhibit some problems of their own,mainly, with respect to the costs of their presence and with respect totheir driving through the entire conveyor system.

SUMMARY OF THE PRESENT INVENTION

According to the present invention, the feeding conveyor is arranged soas to allow for a close juxtaposition of the consecutive trays duringthe passage of the trays through the filling station, such that theconnecting plate elements between relatively narrow trays can beentirely avoided, while care is still taken that the trays are spaced asrequired when passing through the loading station. At the loadingstation is it important whether or not the trays are interconnected bysuch plate elements once the articles have been orderly placed in thetrays.

The invention calls for three main functions of the feeding conveyor,namely, stowing the relatively narrow trays closely together in thefilling station, expanding the distance between the trays as the traysare moved through the loading or transferring station for loading thearticles into the carton members, and moving the emptied trays as quickas possible back to the filling station in a sufficient number to ensurea steady presence of a desired number of stowed trays in the fillingstation.

It will be understood that, in normal continuous operation, there willbe the same number of trays per unit of time passing through any crosssection of the conveying path, namely, given by the operational speed ofthe carton handling line. In the filling station, the closely juxtaposedtrays will thus exhibit the additional advantage of being movedrelatively slowly, such that the attendants can place the articles inthe trays with still further ease.

In accordance with the present invention, an ordinary conveyor chain isemployed for expanding the distance between the trays as they are movedthrough the loading station for loading the articles into the cartonmembers and for moving the empty trays as fast as possible back to thefilling station in a sufficient number to ensure a steady presence ofthe desired number of stowed trays, that is, a conveyor is equipped tocarry the tray units at a pitch at a center distance as given by thecarton handling line, for example, typically some fifteen (15) inches,while, in the filling station, means are provided for releasing the trayunits from their engagement with the chain and transferring units toanother driving system in which the tray units are conveyed slowly andclosely to each other and from which the tray units are consecutivelydelivered back to their engagement with the chain conveyor so as to bebrought through the loading station with the reduced center distance andspeed. Alternatively, the tray units can maintain their engagement withthe chain conveyor even when passing through the filling station namely,if care is taken to reduce the distance between the tray carrying chainportions, leaving the chain slack or bulging out in the spacestherebetween.

In accordance with further features of the invention, a number ofdifferent conveyors may be used for forming the closed conveying path ofthe tray units. In such a system, it is possible to control the centerdistance between the tray units by accelerating and decelerating theunits between the stations in which the center distance should be thesame, large or small. This will require a good deal of controlequipment, but it will largely facilitate the mechanical handling meansand provide for an extreme operational flexibility. The conveyorbringing the tray units from the rear end of the loading station back tothe entrance of the filling station may operate at a high speed, forexample, with a very long distance between the trays, and, accordingly,the total number of tray units in the entire system can be reduced. Thisis particularly relevant where it is desirable to make use of a highnumber of trays operatively present in the filling station. Even withthe use of the first mentioned chained conveyor, it will be possible toarrange for a quick return of the tray units to the filling station, asalso in the return run the tray units may be released from the chain andtransferred to a separate return conveyor for renewed engagement withthe chain conveyor when the tray units leave the filling station.

No matter how the control system is devised, when it is required toswitch to another carton and article width, it will, still be necessaryto replace the tray units with others correspondingly dimensioned trayunits, regardless of the pitch or center distance in the loading stationhaving to be unchanged. In the mechanically controlled system, this willimply a corresponding replacement or adjustment of the conveyor meansbringing the trays through the filling station such that also the newtrays can be brought closely together in this station, while in thesensor controlled plural conveyor system no such replacement will berequired, as merely an adjustment of the control settings will besufficient.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following description, the invention is explained in more detailwith reference to the drawings, wherein:

FIG. 1 is a perspective view of a cartonizer according to the presentinvention,

FIG. 2 is a schematical side view of a tray system according to theinvention,

FIG. 3 is a corresponding top view thereof,

FIG. 4 is a schematic side view of a modified system,

FIG. 5 is a perspective view of a single tray carrier, as viewed frombelow,

FIG. 6 is an end view thereof, and

FIG. 7 is a side or top view of a modified driving element withreference to FIG. 1.

DETAILED DESCRIPTION

The cartonizing apparatus shown in FIG. 1 comprises a table portion A,on which articles to be cartonized in groups can be received, and a rowof trays B for receiving the articles in such groups, arranged by anoperator of the table portion A. The trays are conveyed into thecartonizer section C, in which the article groups are placed in cartonsD which leave the cartonizer on, for example, a conveyor belt.

The system shown in FIG. 1 comprises a driving endless chain conveyor 2and, for example, two chain conveyors may be arranged side by side, withthe chain conveyor 2 having outwardly protruding pins 4 for driving arow of tray conveyors 6 along a rail system 7 defining a path ofmovement of the tray carriers 6, and with each of the protruding pins 4carrying a tray 8. A spacing P between the tray carriers 6 is determinedby requirements set by a co-acting carton handling line 10 in thecartonizer C.

As shown in the left hand portion of FIG. 2, the conveying of the trays8 is accomplished by a substantially horizontally disposed conveyor worm12 provided with a screw or threaded groove 14 adapted to receive adownwardly projecting pin 16 on the tray carriers 6. The conveyor chains2 are guided so as to bypass the conveyor worm 12 out of engagement withthe tray carriers 6, and the guiding rails 7 are arranged such that theguiding rails 7 will guide the tray carriers 6 directly into engagementwith the left hand end of the screw or threaded groove 14 and thereafterstill stabilize the tray carriers 6 during following forced movement ofthe tray carriers 6 along the rotating conveyor worm 12. Inversely, whenleaving the right hand end of the conveyor worm 12, the tray carriers 6will again be engaged by the pins 4 of the driving conveyor chains 2 andthe pins 4 will remain thus engaged and held by the guiding rail 7 untilthe respective pins 4 return to the conveyor worm 12 through the lowerrun of the chain conveyor 2.

The screw or threaded groove 14 of the conveyor worm 12 has a ratherhigh pitch at both ends thereof, while along a middle portion thereof,the pitch is considerably smaller. Consequently, as illustrated, thetrays 8 will be brought together almost so as to touch each other, forexample, the narrower pitch of the conveyor worm 12 is adapted accordingto the width of the trays 8. If the system is rearranged with widertrays it may be required, therefore, to even replace the conveyor worm12.

The area along which the trays 8 are closely juxtaposed will be thefilling area of the supply conveyor B, where articles can be placed inthe trays 8 in a safe and convenient manner partly because the trays 8are located directly side by side and partly because the trays 8 willmove relatively slowly through the filling station.

As shown by the arrows in FIG. 3, when the trays 8 pass along the cartonhandling line 10, the articles on the trays 8 will be laterallydischarged off the trays 8 and into the carton members; the lateraldischarge arrangement may be constructed in a conventional manner and,consequently, will not be further described herein. It is alsoillustrated that the trays 8 are also displaced laterally on the trayconveyors 6 in order to get close to the carton members, but also thisis well known in the art and, of course, the tray carriers should onlybe designed correspondingly.

The trays 8 may well be divided into two or more compartments for pluralarticle packaging. According to a special feature of the invention,there may be arranged, between the filling area and the loading area, astation comprising means for automatically pushing a single article intoa tray compartment, should an empty compartment be detected.

FIG. 4 illustrates a slowly moving conveyor 20 extending along thefilling area and followed by a controlled acceleration conveyor 22delivering trays 8 to a conveyor 24, with the conveyor 24 being adaptedto move the trays through the loading station at the prescribed traypitch P. A separate return conveyor 26 operates at a fast speed forreturning the trays 8 with a pronounced widened pitch such that therewill not be many trays running idly in the return run. From the returnconveyor 26, the trays 8 are transferred to one or more controlleddecelerating conveyors 28, from which the trays 8 are delivered to thefilling conveyor 20.

It will be appreciated that, in a system based on the use of controlledintermediate conveyors between the filling conveyor and the loadingconveyor, it will be possible to replace the trays 8 with broader ornarrower trays 8 as required without replacing the conveyors, as theremaining adaptation will be a question of resetting the controlparameters.

As shown in FIG. 5, the tray carrier 6 includes a block member which isprovided with lateral grooves 30 for cooperation with the guiding railsystem 7, as well as with laterally protruding pin members 32 adapted toreceive upstanding dog members 34 on the chain conveyor 2 such that eachtray carrier can be driven along the guiding rails 7. The chainconveyors 2, see also FIG. 6, are guided in fixed C-shaped rails 36,which, at the beginning and end of the conveyor worm 12, are curved soas to bring the dogs 32 out of an into driving engagement with the traycarrier 6 as these, by way of the lower pins 16 respectively engage anddisengage the worm groove 14.

The trays 8 are mounted on a support 38 which is laterally displaceableon the carrier 6, guided by a rod 40, whereby the trays 8 can carry outthe lateral movements discussed hereinabove in connection with FIG. 3.

The worm groove 14 should not necessarily impart a continuous motion tothe trays 8. For example, as shown in FIG. 7, the worm groove designated14' may be arranged so as to extend, by each turn, in a circular mannerover a part of the circumference of the worm, whereby the closelyjuxtaposed trays 8 will be moved in a stepwise manner.

We claim:
 1. A machine for cartonizing articles, the machine comprisinga filling station in which articles to be cartonized are supplied tocarrier units, a carton erecting station in which cartons aresuccessively prepared for receiving the articles, a transfer station inwhich the articles are successively loaded into the cartons from thecarrier units while the cartons are advanced at a predetermined mutualspacing, and a conveyor system operable to move the carrier units fromthe filling station to and through the loading station, wherein in theloading station, the carrier units are advanced successively with amutual spacing corresponding to that of the cartons, and the conveyorsystem is adapted to advance the carrier units with a reduced mutualspacing during passage of the carrier units through the filling station.2. A machine according to claim 1, wherein the conveyor system comprisesan endless chain adapted to drive the carrier units through the loadingstation with the required mutual spacing between the carrier units andreturned to an entrance of the filling station, a driving means of theconveyor system in the filling station including a rotating worm havinga screw fashioned as one of a driving track or ridge means forcooperation with the carrier units, and wherein said endless chain isadapted to one of bypass the filling station or pass inoperativelythrough said filling station.
 3. A machine for cartonizing articlesaccording to claim 1, wherein the respective article carrying means areclosely juxtaposed during passage through the filling station.